Chain carburizing/carbonitriding + quenching and tempering + surface treatment Description: Strictly speaking, carburizing/carbonitriding is a heat treatment process aimed at improving the surface hardness and wear resistance of chains (the core purpose is to increase strength). However, after heat treatment, the chain must undergo anti-corrosion treatment (such as galvanizing or blackening) to prevent rusting. Application: High-strength lifting chains (such as G80, G100 grades) usually undergo heat treatment such as carburizing and quenching to meet the strength requirements, followed by surface anti-corrosion treatment such as hot-dip galvanizing.